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Sagripanti JL, Voss L, Marschall HJ, David Lytle C. Inactivation of Vaccinia Virus by Natural Sunlight and by Artificial UVB Radiation. Photochem Photobiol 2013; 89:132-8. [DOI: 10.1111/j.1751-1097.2012.01207.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/16/2012] [Indexed: 11/28/2022]
Affiliation(s)
- Jose-Luis Sagripanti
- Research and Technology Directorate; Edgewood Chemical Biological Center; U.S. Army; Aberdeen; MD
| | - Luzie Voss
- Wehrwissenschafliches Institut für Schutztechnologien (WIS); Munster; Germany
| | | | - Carl David Lytle
- Research and Technology Directorate; Edgewood Chemical Biological Center; U.S. Army; Aberdeen; MD
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da Silva Marciano R, da Silva Sergio LP, Polignano GAC, Presta GA, Guimarães OR, Geller M, de Paoli S, de Paoli F, da Fonseca ADS. Laser for treatment of aphthous ulcers on bacteria cultures and DNA. Photochem Photobiol Sci 2012; 11:1476-83. [PMID: 22766761 DOI: 10.1039/c2pp25027f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Low-intensity red lasers are proposed for treatment of oral aphthous ulcers based on biostimulative effects. However, effects of low-intensity lasers at fluences used in clinical protocols on DNA are controversial. The aim of this work was to evaluate the effects of low-intensity red laser on survival and induction of filamentation of Escherichia coli cells, and induction of DNA lesions in bacterial plasmids. Escherichia coli cultures were exposed to laser (660 nm, 100 mW, 25 and 45 J cm(-2)) to study bacterial survival and filamentation. Also, bacterial plasmids were exposed to laser to study DNA lesions by electrophoretic profile and action of DNA repair enzymes. Data indicate that low-intensity red laser: (i) had no effect on survival of E. coli wild type, exonuclease III and formamidopyrimidine DNA glycosylase/MutM protein but decreased the survival of endonuclease III deficient cultures; (ii) induced bacterial filamentation, (iii) there was no alteration in the electrophoretic profile of plasmids in agarose gels, (iv) there was no alteration in the electrophoretic profile of plasmids incubated with formamidopyrimidine DNA glycosylase/MutM protein and endonuclease III enzymes, but it altered the electrophoretic profile of plasmids incubated with exonuclease III. Low-intensity red laser at therapeutic fluences has an effect on the survival of E. coli endonuclease III deficient cells, induces bacterial filamentation in E. coli cultures and DNA lesions targeted by exonuclease III.
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Affiliation(s)
- Roberta da Silva Marciano
- Centro de Ciências da Saúde, Centro Universitário Serra dos Órgãos, Avenida Alberto Torres, 111, Alto, Teresópolis, Rio de Janeiro, 25964004, Brazil
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Fonseca AS, Moreira TO, Paixão DL, Farias FM, Guimarães OR, de Paoli S, Geller M, de Paoli F. Effect of laser therapy on DNA damage. Lasers Surg Med 2010; 42:481-8. [PMID: 20662024 DOI: 10.1002/lsm.20921] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Whereas the biostimulative effect on tissues using low intensity laser therapy for treating many diseases has been described, the photobiological basis and adverse effects are not well understood. The aim of this study, using experimental models, is to observe the combined effect of physical damage (laser) and a chemical agent (hydrogen peroxide) on Escherichia coli cultures and bacterial plasmids. MATERIALS AND METHODS Survival of E. coli AB1157 (wild type) and BW9091 (xth(-)) cultures were used as an experimental model to assess the effect of agents on DNA, also agarose gel electrophoretic profile of bacterial plasmids for studying single and double strand breaks in DNA exposed to laser irradiation and in DNA pre-exposed to laser and subsequently incubated with hydrogen peroxide. RESULTS Data indicate low intensity laser: (i) did not alter the survival of E. coli cultures, (ii) pre-exposure had a protective effect against lethal action of hydrogen peroxide on E. coli cultures, and (iii) did not alter the electrophoretic profile and action of hydrogen peroxide on plasmids. This suggests that low intensity therapeutic red laser doses at different emission modes induces sub-lethal effects on E. coli wild type and exonuclease III mutant cultures inducing protective mechanisms against lethal action of hydrogen peroxide. Laser action on bacterial plasmids is related to lesions other than single or double DNA strands breaks. CONCLUSIONS This study shows a protective effect or DNA repair mechanism induction by pre-exposure to low intensity red laser on the lethal action of oxidant agents and, therefore, laser therapy protocol should consider fluencies, wavelength and tissue conditions before beginning treatment.
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Affiliation(s)
- Adenilson S Fonseca
- Departamento de Ciências Fisiológicas, Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, Rua Frei Caneca, 94, Rio de Janeiro 20211040, Brazil.
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Coohill TP, Sagripanti JL. Bacterial inactivation by solar ultraviolet radiation compared with sensitivity to 254 nm radiation. Photochem Photobiol 2009; 85:1043-52. [PMID: 19659922 DOI: 10.1111/j.1751-1097.2009.00586.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Our goal was to derive a quantitative factor that would allow us to predict the solar sensitivity of vegetative bacterial cells to natural solar radiation from the wealth of data collected for cells exposed to UVC (254 nm) radiation. We constructed a solar effectiveness spectrum for inactivation of vegetative bacterial cells by combining the available action spectra for vegetative cell killing in the solar range with the natural sunlight spectrum that reaches the ground. We then analyzed previous studies reporting the effects of solar radiation on vegetative bacterial cells and on bacterial spores. Although UVC-sensitive cells were also more sensitive to solar radiation, we found no absolute numerical correlation between the relative solar sensitivity of vegetative cells and their sensitivity to 254 nm radiation. The sensitivity of bacterial spores to solar exposure during both summer and winter correlated closely to their UVC sensitivity. The estimates presented here should make it possible to reasonably predict the time it would take for natural solar UV to kill bacterial spores or with a lesser degree of accuracy, vegetative bacterial cells after dispersion from an infected host or after an accidental or intentional release.
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Clauss M, Grotjohann N. Comparative mutagenesis of Escherichia coli strains with different repair deficiencies irradiated with 222-nm and 254-nm ultraviolet light. Mutat Res 2009; 673:83-6. [PMID: 19146982 DOI: 10.1016/j.mrgentox.2008.11.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 11/17/2008] [Accepted: 11/30/2008] [Indexed: 10/21/2022]
Abstract
Photoinactivation and reversion to tryptophan prototrophy were studied in four Escherichia coli strains with different repair deficiencies. Cells were irradiated with 222-nm wavelength UV emitted by an excimer lamp and with 254-nm wavelength UV emitted by a low-pressure mercury lamp. Strain DSM 9494 (trp(-)uvrA(+)) turned out to be most resistant while the strain DSM 9495 (trp(-)uvrA(-)), which is defective in nucleotide-excision repair (NER) was most sensitive to both wavelengths. UV-fluence rates for a respective inactivation were twice as high for 222-nm wavelength UV than for 254-nm UV. No clear difference in efficiency of inactivation could be observed between the two wavelengths in strains DSM 9496 (trp(-)uvrA(+) pKM101) and DSM 9497 (trp(-)uvrA(-) pKM101). In general, more revertants were induced by 254-nm wavelength UV, which corroborates the hypothesis that a higher amount of DNA damage was induced by this wavelength than by 222-nm UV, except for DSM 9497 where no clear difference could be observed regarding the number of revertants induced by both wavelengths. This strain DSM 9497 has a high sensitivity to certain oxidative mutagens compared with other strains, which is indicative of formation of reactive oxygen species during irradiation with 222-nm wavelength UV.
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Affiliation(s)
- Marcus Clauss
- Faculty of Biology, University of Bielefeld, Universitätsstrasse 25, 33615 Bielefeld, Germany.
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Shennan MG, Palmer CM, Schellhorn HE. Role of Fapy glycosylase and UvrABC excinuclease in the repair of UVA (320-400 nm)-mediated DNA damage in Escherichia coli. Photochem Photobiol 1996; 63:68-73. [PMID: 8577867 DOI: 10.1111/j.1751-1097.1996.tb02993.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In contrast to the damage caused by far-UV, the damage caused by UVA (320-400 nm) is largely oxygen dependent, suggesting near-UV-mediated DNA damage involves reactive oxygen species. The DNA repair enzymes that recognize oxidized bases may, therefore, be an important part of the cell's near-UV defense repertoire. To evaluate the relative importance of Fpg (Fapy) glycosylase (an enzyme known to remove oxidized bases) and the DNA damage-inducible UvrABC excinuclease in recovery from near-UV-induced stress, we have constructed fpg- and uvrA- derivatives of Escherichia coli and tested the response (survival) of these strains to both UVA and far-UV radiation. Relative to control strains, the fpg- derivatives were found to be consistently more sensitive to the lethal effects of UVA, but not far-UV radiation. In contrast, uvrA- mutants were more sensitive than control strains to both UVA and far-UV radiation. Thymine dimers, known to be produced by far-UV and corrected by UvrABC, were not generated by the UVA fluences used in this study, suggesting that some other UVA-induced lesion(s) is recognized and repaired by this excinuclease.
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Affiliation(s)
- M G Shennan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Knowles RL, Eisenstark A. Near-ultraviolet mutagenesis in superoxide dismutase-deficient strains of Escherichia coli. ENVIRONMENTAL HEALTH PERSPECTIVES 1994; 102:88-94. [PMID: 9719674 PMCID: PMC1567244 DOI: 10.1289/ehp.9410288] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We compared mutagenic spectra induced by polychromatic near-ultraviolet radiation (near-UV; 300-400 nm) with superoxide anion (O2-) -dependent mutagenesis using a set of Escherichia coli tester strains. Near-UV radiation produced increased frequencies of G:C to A:T transitions, G:C to T:A and A:T to T:A transversions, and small increases in frameshift mutations in wild-type cells. Tester strains lacking superoxide dismutase (SOD) activity (sodAsodB double mutants) demonstrated high spontaneous mutation frequencies and increased near-UV sensitivity. The double mutants also showed increased mutations induced by near-UV compared to either isogenic wild type, sodA or sodB single mutants. Furthermore, these mutants had an unusual spontaneous mutation spectrum, with a predominance of A:T to T:A transversions, followed by G:C to T:A transversions and frameshifts generated in runs of adenines in both the +1 and -1 direction. Other frameshifts were detected to a lesser degree. The oxygen dependency and the type of mutations spontaneously induced in SOD-deficient cells indicated that this mutagenic spectrum was caused by oxidative DNA damage. However, no apparent synergistic action between near-UV radiation and an increased flux of O2- could be detected. From the frequency and types of mutations induced by the two agents, we speculate that near-UV-induced mutagenesis and O2--dependent mutagenesis involve, in part, different lesion(s) and/or mechanism(s). The nature and possible mutagenic pathways of each are discussed.
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Affiliation(s)
- R L Knowles
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211 USA
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Abstract
The most common fluorescent lamps in use today in homes and businesses in the United States, 'coolwhite' fluorescent lamps, emit light that is mutagenic for Salmonella. Strains that carry both a uvrB mutation and plasmid pKM101 are extremely susceptible to this light-induced mutation. Both base substitution and frameshift mutations can be induced without substantial lethal effects on the bacteria. Induced mutations accumulate essentially as a linear function of the time bacteria are exposed to illumination. Of Salmonella histidine-requiring strains with known nucleotide target sequences (Hartman et al., 1986; Cebula and Koch, 1989, 1990), strains either carrying one of the base substitution mutations, hisG428 and hisG46, or one of the frameshifts, hisC3076 and hisD6610, are most highly mutagenized whereas frameshift strains with hisD6580 and hisD3052 exhibit lower rates of mutagenesis. Mutagenicity does not appear to require the presence of oxygen. A filter blocking wavelengths below 370 nm eliminates mutagenesis. Polystyrene, cellulose acetate and, especially, mylar and glass filters reduce mutagenesis, indicating that at least some of the mutagenic effects can be attributed to leakage of radiations below 290 nm (far-ultraviolet light) from 'coolwhite' lamps. The more recently introduced fluorescent 'softwhite' lamps are roughly 10-fold less mutagenic at approximately equal light intensity. Incandescent light bulbs are much less mutagenic than are these fluorescent lamps. Our mutational data correlate closely with previous results in eukaryotic cells (Jacobson and Krell, 1982). A uvrB recA Salmonella double mutant is hypersensitive to the lethal effects of coolwhite fluorescent light, even when illuminated through the lids of glass Petri dishes. Thus, appropriate Salmonella strains would appear to be simple and useful screens for both the mutagenic and the lethal activities of fluorescent lamps. These systems are amenable to classroom laboratory use as relatively safe and effective means of demonstrating environmental mutagenesis.
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Affiliation(s)
- Z Hartman
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
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Lloyd RE, Rinkenberger JL, Hug BA, Tuveson RW. Growing Escherichia coli mutants deficient in riboflavin biosynthesis with non-limiting riboflavin results in sensitization to inactivation by broad-spectrum near-ultraviolet light (320-400 nm). Photochem Photobiol 1990; 52:897-901. [PMID: 2089438 DOI: 10.1111/j.1751-1097.1990.tb08699.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Two mutants of Escherichia coli unable to synthesize riboflavin were grown with limiting (2 micrograms ml-1) and non-limiting (10 micrograms ml-1) concentrations of riboflavin. These riboflavin auxotrophs when grown to exponential phase with non-limiting riboflavin are more sensitive to broad spectrum near-ultraviolet light (NUV, 320-400 nm) inactivation than when they are grown with limiting riboflavin. Exponential phase cells of the riboflavin auxotrophs grown with limiting riboflavin are sensitized when irradiated in saline supplemented with riboflavin. This suggests that extracellular riboflavin is important as a NUV sensitizer when intracellular levels of riboflavin are reduced. The concentration of riboflavin in crude extracts from exponentially growing cells correlates well with the sensitivity of these mutants to NUV inactivation. The level of riboflavin supplementation has little effect on the NUV sensitivity of the parental strain.
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Affiliation(s)
- R E Lloyd
- Department of Microbiology, University of Illinois, Urbana 61801
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Hoerter J, Eisenstark A, Touati D. Mutations by near-ultraviolet radiation in Escherichia coli strains lacking superoxide dismutase. Mutat Res 1989; 215:161-5. [PMID: 2557549 DOI: 10.1016/0027-5107(89)90179-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In wild-type Escherichia coli, near-ultraviolet radiation (NUV) was only weakly mutagenic. However, in an allelic mutant strain (sodA sodB) that lacks both Mn- and Fe-superoxide dismutase (SOD) and assumed to have excess superoxide anion (O2-), NUV induced a 9-fold increase in mutation above the level that normally occurs in this double mutant. When a sodA sodB double mutant contained a plasmid carrying katG+ (excess HP-I catalase), mutation by NUV was reduced to wild-type (sodA+ sodB+) levels. Also, in the sodA sodB xthA triple mutant, which lacks exonuclease III (exoIII) in addition to SOD, the mutational frequency by NUV was reduced to wild-type levels. This synergistic action of NUV and O2- suggested that pre-mutational lesions occur, with exoIII converting these lesions to stable mutants. Exposure to H2O2 induced a 2.8-fold increase in mutations in sodA sodB double mutants, but was reduced to control levels when a plasmid carrying katG+ was introduced. These results suggest that NUV, in addition to its other effects on cells, increases mutations indirectly by increasing the flux of OH. radicals, possibly by generating excess H2O2.
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Affiliation(s)
- J Hoerter
- Division of Biological Sciences, University of Missouri, Columbia 65211
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Eisenstark A. Bacterial genes involved in response to near-ultraviolet radiation. ADVANCES IN GENETICS 1989; 26:99-147. [PMID: 2683610 DOI: 10.1016/s0065-2660(08)60224-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A model of the possible pathways of activities following NUV treatment was presented in Section I and in Fig. 1. Some of the components are firmly established, some are speculative, and many are difficult to evaluate because of insufficient experimental information. Perhaps the most relevant experiments, especially concerning ozone depletion, would be to determine the mutational specificity of NUV. By selecting lacI mutants after exposing cells to NUV, and sequencing the bases of this gene, this is now feasible. There are some problems, however. The mutation frequency is normally so low that it might be difficult to distinguish NUV mutants from spontaneous mutants. However, by irradiating cells having a uvrA or uvrB mutation, the frequency of mutation above background can be increased considerably. There remains the problem as to what fraction of the observed mutations results from oxidative damage. Some of this could be clarified by comparing mutation spectra of cells treated with NUV and cells subjected to excess oxidative damage and determining what fraction results from other avenues of lesion formation in DNA. Different species of reactive oxygen could cause different kinds of DNA lesions, and, fortunately, use of appropriate mutants should allow us to sort out any differences in specificity of lesions. Also, by appropriate manipulation of quantities of endogenous photosensitizers, it might be possible to sort out the specific mutations that are caused by photodynamic action. Another avenue of research is to explore the pathways by which NUV lesions are repaired, and whether such repair is error prone or error free. Again, the use of mutants such as xthA, uvr, and polA should assist in our understanding of the specificity of the mutational events. There are now a number of examples of global control mechanisms whereby cells abruptly shift their protein synthesis pattern under environmental stress. It is important to understand whether NUV stress results in induction of one or more of the known regulatory genes, or whether another regulon might be involved. One particular aspect of regulation that remains unsolved is the role of the katF gene, which is known to regulate the xthA and katE, but it may also regulate other genes as well. A number of striking physiological events occur even at very low fluences of NUV irradiation of cells. In part, this may be related to regulon induction. However, some of these events are in need of special exploration, such as changes at the membrane level.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- A Eisenstark
- Division of Biological Sciences, University of Missouri, Columbia 65211
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Lundgren K, Wulf HC. Cytotoxicity and genotoxicity of UVA irradiation in Chinese hamster ovary cells measured by specific locus mutations, sister chromatid exchanges and chromosome aberrations. Photochem Photobiol 1988; 47:559-63. [PMID: 3406117 DOI: 10.1111/j.1751-1097.1988.tb08844.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Eisenstark A. Mutagenic and lethal effects of near-ultraviolet radiation (290-400 nm) on bacteria and phage. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1987; 10:317-337. [PMID: 3315655 DOI: 10.1002/em.2850100311] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Despite decades of study of the effect of near-ultraviolet radiation (NUV) on bacterial cells, insights into mechanisms of deleterious alterations and subsequent recovery are just now emerging. These insights are based on observations that 1) damage by NUV may be caused by a reactive oxygen molecule, since H2O2 may be a photoproduct of NUV; 2) some, but not all, of the effects of NUV and H2O2 are interchangeable; 3) there is an inducible regulon (oxyR) that responds to oxidative stress and is involved in protection against NUV; 4) a number of NUV-sensitive mutants are defective either in the capacity to detoxify reactive oxygen molecules or to repair DNA damage caused by NUV; and 5) recovery from NUV damage may not directly involve induction of the SOS response. Since several distinctly different photoreceptors and targets are involved, it is unknown whether NUV lethality and mutagenesis result from an accumulation of damages or whether there is a particularly critical photoeffect. To fully understand the mechanisms involved, it is important to identify the chromophore(s) of NUV, the mechanism of toxic oxygen species generation, the role of the oxidative defense regulon (oxyR), the specific lesions in the DNA, and the enzymatic events of subsequent repair.
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Affiliation(s)
- A Eisenstark
- Division of Biological Sciences, University of Missouri, Columbia 65211
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Hitchins VM, Withrow TJ, Olvey KM, Harleston BA, Ellingson OL, Bostrom RG. The cytotoxic and mutagenic effects of UVA radiation on L5178Y mouse lymphoma cells. Photochem Photobiol 1986; 44:53-7. [PMID: 3749293 DOI: 10.1111/j.1751-1097.1986.tb03563.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Tuveson RW, Sammartano LJ. Sensitivity of hemA mutant Escherichia coli cells to inactivation by near-UV light depends on the level of supplementation with delta-aminolevulinic acid. Photochem Photobiol 1986; 43:621-6. [PMID: 3529139 DOI: 10.1111/j.1751-1097.1986.tb05637.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Abstracts. Photochem Photobiol 1985. [DOI: 10.1111/j.1751-1097.1985.tb08912.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sammartano LJ, Tuveson RW. The effects of exogenous catalase on broad-spectrum near-UV (300-400 nm) treated Escherichia coli cells. Photochem Photobiol 1984; 40:607-12. [PMID: 6393153 DOI: 10.1111/j.1751-1097.1984.tb05348.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Peak MJ, Peak JG, Moehring MP, Webb RB. Ultraviolet action spectra for DNA dimer induction, lethality, and mutagenesis in Escherichia coli with emphasis on the UVB region. Photochem Photobiol 1984; 40:613-20. [PMID: 6393154 DOI: 10.1111/j.1751-1097.1984.tb05349.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Eisenstark A. Genetic damage in Salmonella typhimurium by near-ultraviolet radiation. Lack of repair by plasmid pKM101. Mutat Res 1983; 122:267-72. [PMID: 6361536 DOI: 10.1016/0165-7992(83)90005-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Plasmid pKM101, whose mucA and B genes endow cells with enhanced mutation frequency and enhanced resistance to far-ultraviolet radiation (FUV) (254 nm), had no influence on these properties when cells were damaged by near-ultraviolet radiation (NUV) (300-400 nm). Thus, NUV lesions did not lead to induction of SOS repair and subsequent expression of mucA and B genes on plasmid pKM101. Further, when cells were pre-irradiated with NUV and subsequently irradiated with FUV, there was a blockage of SOS repair, including the repair normally controlled by genes on pKM101.
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Webb RB, Tuveson RW. Differential sensitivity to inactivation of nur and nur+ strains of Escherichia coli at six selected wavelengths in the UVA, UVB and UVC ranges. Photochem Photobiol 1982; 36:525-30. [PMID: 6757985 DOI: 10.1111/j.1751-1097.1982.tb04411.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Webb RB, Turner MA. Mutation induction by monochromatic 254-nm and 365-nm radiation in strains of Escherichia coli that differ in repair capability. Mutat Res 1981; 84:227-37. [PMID: 7038450 DOI: 10.1016/0027-5107(81)90192-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Mutation to tryptophan independence after exposure to radiation at the monochromatic wavelengths of 254 and 365 nm was studied and compared in 7 strains of Escherichia coli B/r that differ in repair capability. Efficient mutation induction was obtained with both 254-nm and 365-nm radiation with strains WP2 (wild-type), WP2s (uvrA), WP6s (polA), and WP6 (polA uvrA). Mutants were not induced at either wavelength in the lexA strain WP5 or the recA strains WP10 and WP100. These results support the induction of mutants with 365-nm radiation through the error-prone (SOS) pathway of postreplication repair. Log-log plots of tryptophan revertant data at 254 nm showed the expected slopes of approximately 2.0 over the entire fluence range tested. In contrast, similar plots of revertant data at 365 nm were complex in all cases tested: at low fluence values (survival greater than 0.5) in all cases where reversion occurred the slopes were approximately 1.0, while at higher fluences (survival less than 0.5) the slopes of the log-log plots were approximately 3.0 with strains WP2s and WP6s, approximately 4.0 with strain WP6, and approximately 6.0 with strain WP2. Differential sensitivity of components of excision and postreplication repair systems to 365-nm radiation may account for the 2-part mutation curves obtained with uvr+ rec+ lex+ strains. It is proposed that efficient error-free repair of mutational lesions occurs at 365-nm fluences below 2-4 x 10(5) J m-2; at greater 365-nm fluences, error-free excision repair may be selectively inhibited, forcing a greater fraction of mutational lesions to be processed by the error-prone component of the postreplication repair system. The similarity of the mutational responses of WP2s and WP6 at 365 nm supports the selective inhibition of error-free excision repair.
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